Truly integrated, quantitative, 3D GEOmetallurgical (or mineral system) characterisation, classification and 3D modelling should provide a cradle to grave unifying link across the exploration and mining value chain. All too often, spatially representative (quantitative) characterisation and modelling of a mineral system is delayed until feasibility stage, incurring a significant opportunity cost. The application of robust GEOmet characterisation methods early in the project lifecycle (at exploration stage) improves ground selection, exploration, and Mineral Resource estimation outcomes, long before there is a need for metallurgical test work. The value of this early provision of quantitative 3D mineralogy models is compounded at project feasibility stage, and continues to accrue over the entire project lifecycle, delivering cost savings, improved decision making and early warning of issues and opportunities.CITATION: Potma, W, Halley, S, Scogings, A, Urbisinov, S and Brauhart, C, 2018. Putting the GEO' back in front of GEOmetallurgy: importance of early implementation of quantitative mineral system characterisation, classification and modelling, in Proceedings Complex Orebodies Conference 2018, pp 55-57 (The Australasian Institute of Mining and Metallurgy: Melbourne).